diff --git a/pkgs/by-name/op/opensc/package.nix b/pkgs/by-name/op/opensc/package.nix
index 93f3ce21112d..8d8d27d337b8 100644
--- a/pkgs/by-name/op/opensc/package.nix
+++ b/pkgs/by-name/op/opensc/package.nix
@@ -67,7 +67,7 @@ stdenv.mkDerivation (finalAttrs: {
     "completiondir=$(out)/etc"
   ];
 
-  passthru.updateScript = nix-update-script { extraArgs = [ "--version-regex=^([0-9\.]+)$" ]; };
+  passthru.updateScript = nix-update-script { extraArgs = [ "--version-regex=^([0-9\\.]+)$" ]; };
 
   meta = {
     description = "Set of libraries and utilities to access smart cards";